Surfactant, and an emulsion-type cosmetic composition and a liposome containing said surfactant

ABSTRACT

The invention provides a surfactant comprising at least one trehalose-6-fatty acid ester selected from those represented by the following formula:  
                 
 
     wherein R represents a saturated or unsaturated acyl group having 8-22 carbon atoms, and may have a hydroxyl group or other substituents, and an emulsion-type cosmetic composition comprising said surfactant and a water-soluble polymer. The surfactant of the invention has excellent surface activity and safety. Also, the emulsion-type cosmetic composition has excellent long-term storage stability and sensory properties, has no irritation to skin, and gives beautiful appearance with fine surface texture. Further, the invention is a liposome having a membrane wall composed of trehalose fatty acid ester. Said liposome has excellent chemical and physical stabilities such as long-term storage stability.

FIELD OF THE INVENTION

[0001] The present invention relates to a surfactant which has excellentsurface activity and safety.

[0002] The invention also relates to a detergent with excellent safety,containing the surfactant.

[0003] The invention further relates to an emulsion-type cosmeticcomposition with excellent emulsion stability, safety to skin andsensory properties, containing the surfactant.

BACKGROUND OF THE INVENTION

[0004] A number of compounds are known as surfactants and used in manyapplications. However, most of those surfactants irritate skin when theyare used in cosmetics, such as shampoos, rinses, soaps and othercosmetic compositions, which contact with a human body directly.Therefore, lower irritating surfactants have been desired.

[0005] In many emulsions use is made of nonionic surfactants having apolyoxyethylene chain, anionic surfactants such as fatty acid soaps,cationic surfactants or ampholytic surfactants. However, there was aproblem that emulsion-type cosmetic compositions with those syntheticsurfactants generally tend to irritate skin. Also, even with nonionicsurfactants which are said to be less irritating, most of them fitpoorly to skin because of their polyoxyethylene chains.

[0006] On the other hand, alkylesterified sugars are nonionicsurfactants which have been used widely in foods, cosmetics and thelike. Among others, sucrose alkylesters in which sucrose constitutes asugar skeleton are used widely and seen in many publications (JapanesePatent Application Laid Open No. 56-55306/1981). However, those areinsufficient in sensory properties and long-term storage stability.Also, it is known to use, as a surfactant, trehalose-6,6′-dialkylesterin which a trehalose derivative constitutes a sugar skeleton (JapanesePatent Application Laid Open Nos. 60-25819/1985 and 62-91236/1987).Those are insufficient in emulsifiability.

[0007] Synthesis of trehalose fatty acid ester are reported in Chem.Phar. Bull., 30 (4) pp1169-1174, (1982), where synthesis of6-stearoyl-trehalose and 6,6′-distearoyl-trehalose and the analysis ofthem using NMR, etc. are described. Those esters are reported to haveanti-tumor activity against Ehrlich ascites tumor in mice. There is nodescription or suggestion that they show properties as a surfactant. Anemulsion-type anti-tumor agent is known in which a specific emulsifiercomposition is combined with trehalose-6,6′-difatty acid ester as ananti-tumor agent in order to solve a disadvantage that the ester isdifficult to dissolve in water (Japanese Patent Application Laid OpenNo. 61-289038/1986).

[0008] In consideration of surface activity, foamability, washingability and so forth for a surfactant, the presence of a singlelipophilic moiety is said to be preferred. For example, glucose fattyacid monoester is reported in Japanese Patent Application Laid Open No.03-157349/1991. However, this has a disadvantage that a stable emulsioncan not be obtained due to its weak hydrophilicity.

DISCLOSURE OF THE INVENTION

[0009] A purpose of the invention is to provide a surfactant that hasexcellent surface activity and safety.

[0010] Another purpose of the invention is to provide a detergent thathas excellent safety.

[0011] A further purpose of the invention is to provide an emulsion-typecosmetic that has low irritation to skin, long-term storage stability,excellent sensory properties and beautiful appearance with fine surfacetexture.

[0012] The present invention is a surfactant containing one or more oftrehalose-6-fatty acid esters represented by the following formula:

[0013] wherein R represents a saturated or unsaturated acyl group having8-22 carbon atoms, and may have substituents such as a hydroxyl group.

[0014] One preferred embodiment of the invention is a surfactantcontaining 6-(10-undecylenyl)-trehalose represented by the followingformula:

[0015] Another preferred embodiment of the invention is a surfactantcontaining 6-lauroyl-trehalose.

[0016] Further, another preferred embodiment of the invention is asurfactant containing 6-stearoyl-trehalose.

[0017] Also, the invention is a detergent characterized in that itcontains a surfactant containing one or more of trehalose-6-fatty acidesters represented by the following formula:

[0018] wherein R is a saturated or unsaturated acyl group having 8-22carbon atoms, and may have substituents such as a hydroxyl group.

[0019] Further, the invention is an emulsion-type cosmetic compositioncharacterized in that it contains one or more of trehalose-6-fatty acidesters represented by the following formula:

[0020] wherein R is a saturated or unsaturated acyl group having 8-22carbon atoms, and may have substituents such as a hydroxyl; and

[0021] a water-soluble polymer.

BEST MODE OF THE INVENTION

[0022] The trehalose-6-fatty acid ester of the invention can be obtainedby a condensation reaction of trehalose with a fatty acid or by an esterinterchange reaction between trehalose and a fatty acid ester.

[0023] Examples of the fatty acid or fatty acid ester which can be usedin the invention include synthetic fatty acids and esters thereof,natural fatty acids, such as soybean fatty acid, beef tallow, cottonseed oil, olive oil, palm oil and so forth, and fatty acid estersthereof with lower alkyl groups, which esters are obtained in anyconventional method.

[0024] Trehalose which can be used in the invention may be α,α-trehalose, α,β-trehalose, β,β-trehalose or mixtures thereof.

[0025] The trehalose-6-fatty acid of the invention can be obtained inany usual method of producing sucrose alkyl esters, as described in U.S.Pat. Nos. 2,893,990 and 3,963,699, Japanese Patent Application Laid Openlaid Nos. 36-21717/1961 and 53-6130/1978, all of which are incorporatedherein by reference.

[0026] The trehalose-6-fatty acid ester is obtained as a main reactionproduct in these methods. In some cases, there are contained smallamounts of unreacted trehalose and trehalose-6,6′-fatty acid diester asa side-reaction product. The trehalose-6-fatty acid ester may bepurified in a conventional manner before used, if desired. However, thetrehalose-6-fatty acid may be used together with small amounts ofunreacted trehalose and trehalose-6,6′-fatty acid diester, because thetrehalose-6-fatty acid can exhibit surface activity even in the presenceof them.

[0027] The trehalose-6-fatty acid ester used in the invention ispreferably those in which a fatty acid radical, i.e. an acyl group, hasa linear or branched, saturated alkyl or alkenyl group having 8-22carbon atoms. Examples of those include trehalose monocaprylate,trehalose monononanoate, trehalose monocaprate, trehalosemonoundecanoate, trehalose monolaurate, trehalose monomyristate,trehalose monopalmitate, trehalose monostearate, trehalosemonoarachidate, trehalose monobehenate, trehalose monoundecylenate,trehalose monooleate, trehalose monolinoleate, trehalose monolinolenate,trehalose monoisostearate, trehalose monohydroxystearate, and trehalosemonoricinoleate. One or more from these trehalose-6-fatty acid esterscan be used in the invention.

[0028] The surfactant of the invention preferably contains one or moreselected from 6-(10-undecylenyl)-trehalose, 6-lauroyl-trehalose and6-stearoyl-trehalose.

[0029] The surfactant of the invention has excellent surface activityand safety to skin and also may be used as an emulsifier in foods.

[0030] The skin or hair washing agent detergent of the inventionpreferably contains one or more of the trehalose-6-fatty acid ester inan amount of 1-50 wt. %, particularly 10-35 wt. %. It may furthercontain other surfactants.

[0031] The cosmetic composition of the invention contains one or more ofthe above trehalose-6-fatty acid ester and a water-soluble polymer. Thecontent of the above trehalose-6-fatty acid ester in the cosmeticcomposition is preferably 0.01-20 wt. %, particularly 0.1-10 wt. %,based on the total weight of the cosmetic composition. If the content isless than 0.01 wt. %, the emulsion stability of the cosmetic compositiontends to decrease during its storage. On the other hand, if it is morethan 20 wt. %, it is difficult to obtain fine feeling in use.

[0032] The water-soluble polymer used in the invention may be generallyany of those used in cosmetic compositions or pharmaceutical bases.Examples of the water-soluble polymer include guar gum, roastbean gum,queensseed, carageenan, galactan, arabic gum, tragacanth, pectin,mannan, starch, xanthan gum, dextrin, succinoglucan, curdlan, gelatin,casein, albumin, collagen, methyl cellulose, ethyl cellulose,hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethylcellulose, methylhydroxypropyl cellulose, soluble starch, carboxymethylstarch, methyl starch, propyleneglycol alginate, salts of alginic acid,polyvinylalcohol, polyvinylpyrrolidone, polyvinylmethylether,carboxyvinyl polymers, sodium polyacrylate, polyethyleneglycol, ethyleneoxide/propylene oxide copolymers, cationated cellulose, sodiumchondroitin sulfate, and sodium hyaluronate. These water-solublepolymers may be used alone or in combination.

[0033] The content of the above water-soluble polymer is preferably0.001-40 wt. %, particularly 0.01-20 wt. %, on the basis of the totalweight of the cosmetic composition. If the content is less than 0.001wt. %, the emulsion stability of the cosmetic composition tends todecrease during its storage. On the other hand, if it is more than 40wt. %, it is difficult to obtain fine feeling in use.

[0034] The cosmetic composition of the invention may contain one or moreoil substances that can usually be used in cosmetic compositions orpharmaceutical bases, if necessary, such as hydrocarbons, such as liquidparaffin, squalane, vaseline and microcrystalline wax; ester oils, suchas isopropylmyristate, cetyl-2-ethylhexalate,glyceryl-tri-2-ethylhexanoate, vitamin C palmitate, vitamin C stearate,vitamin C sulfate and vitamin E acetate; waxes, such as beeswax andspermaceti; vegetable oils, such as avocado oil, almond oil, rice branoil, olive oil, castor oil, rapeseed oil, saffron oil, corn oil, wheatgerm oil, soybean oil, cotton-seed oil, tea-seed oil and jojoba oil;animal oils, such as turtle oil, mink oil and yolk oil; higher alcohols,such as cetyl alcohol, stearyl alcohol, oleyl alcohol, octyldodecanoland behenyl alcohol; higher fatty acids, such as laurylic acid, myristicacid, palmitic acid, stearic acid, oleic acid, linolic acid, linolenicacid, ricinoleic acid and isostearic acid; silicone oils, such asdimethylsilicone, methylphenylsilicone and cyclic silicone; othersilicone resins and silicone polymers.

[0035] The cosmetic composition of the invention may contain polyvalentalcohols, such as ethyleneglycol, propyleneglycol, 1,3-butyleneglycol,dipropyleneglycol, glycerin, and polyglycerins such as diglycerin,triglycerin, tetraglycerin, pentaglycerin and hexaglycerin;trimethylolpropane, 1,2,6-hexatriol, glucose, maltose, maltitol,sucrose, fructose, xylitol, mannitol, sorbitol, maltotriose, threitol,sorbitan, starch-decomposed sugar and starch decompoed reducing alcohol,alone or in combination thereof.

[0036] The cosmetic composition of the invention may contain anyingredients customarily used in cosmetics and pharmaceutical bases, suchas humectants, active ingredients, fragrances, preservatives, colorants,UV absorbents, astringents, synthetic surfactants, pigments (e.g.,kaolin, mica, sericite, talc, yellow iron oxide, red iron oxide andtitanium oxide) and water.

[0037] The cosmetic composition of the invention includes massagecreams, cleansing creams, skin creams, foundation creams, makeup bases,hair creams, massage jellys, and medicinal jellys, but is not limited tothose.

[0038] The invention will be explained further in detail in reference tothe following Examples, but shall not be limited to those.

Preparation of trehalose-6-fatty Acid Ester EXAMPLE 1 Preparation of6-(10-undecylenyl)-trehalose

[0039] a) One hundred grams of α,α-trehalose were dissolved in 400 ml ofdimethylformamide, to which added were 52.4 g of methyl 10-undecylenateand 1.0 g of potassium hydroxide, heated to 100° C. and then stirred for12 hours. After this reaction solution was cooled, unreacted methyl10-undecylenate was removed by extracting the solution with 400 ml ofhexane three times. The dimethylformamide solution containing thedesired substance was concentrated to about 200 ml in vacuum, to which,then, 1,000 ml of acetone was added to precipitate unreacted trehalosewhich was subsequently filtered out. The precipitate were washed with100 ml of n-butanol, and the washing liquid was combined with the abovefiltrate. The filtrate was distilled in vacuum to obtain a yellowishviscous syrup. This viscous syrup was subjected to silica gelchromatography (developing solvent: chloroform/methanol=4/1) so as toremove remaining unreacted substances. A fraction containing the desiredsubstance was distilled in vacuum to obtain 24.3 g of a yellowishviscous syrup.

[0040] b) The resultant syrup was analyzed by ¹³C-NMR spectroscopy.Signals were confirmed for a carbonyl group at 175.5 ppm, terminalmethylene group at 140.11 and 114.73 ppm, and 6- and 6′-positions oftrehalose at 64.4 and 62.64 ppm. This indicates the formation of6-(10-undecylenyl)-trehalose.

EXAMPLE 2 Preparation of 6-lauroyl-trehalose

[0041] The procedures of Example 1a) were repeated with the exceptionthat 62.5 g of methyl laurate was used instead of 52.4 g of methyl10-undecylenate. 27.3 g of a white solid were obtained.

[0042] The resultant white solid was analyzed by ¹³C-NMR spectroscopy.Signals were confirmed for a carbonyl group at 175.5 ppm, and 6- and6′-positions of trehalose at 64.4 and 62.64 ppm. The solid was analyzedby FAB-MS spectrometry with NaI and a peak at 547(M(molecular weight ofthe parent peak)+23) was confirmed. These indicate the formation of6-lauroyl-trehalose.

EXAMPLE 3 Preparation of 6-stearoyl-trehalose

[0043] The procedures of Example 1a) were repeated with the exceptionthat 87.1 g of methyl stearate was used instead of 52.4 g of methyl10-undecylenate. 32.1 g of a white solid was obtained. The resultantwhite solid was analyzed by FAB-MS spectrometry with NaI and a peak at631(M(molecular weight of the parent peak)+23) was confirmed. Thisindicates the formation of 6-stearoyl-trehalose.

EXAMPLE 4 Preparation of trehalose-6-soybean Fatty Acid Ester

[0044] One hundred grams of α,α-trehalose were dissolved in 400 ml ofdimethylformamide. To this solution added were 60 g of a methyester ofsoybean fatty acid and 1.0 g of potassium hydroxide, heated to 100° C.,and then stirred for 18 hours. After this reaction solution was cooled,the unreacted methylester of soybean fatty acid was removed byextracting the reaction solution with 400 ml of hexane five times. Thedimethylformamide solution containing the desired substance wasconcentrated to about 200 ml in vacuum, to which 1,500 ml of acetone wasadded to precipitate unreacted trehalose which was subsequently filteredoff. The precipitates were washed with 100 ml of n-butanol, and thewashing liquid was combined with the above filtrate. The filtrate wasdistilled in vacuum to obtain 41.6 g of trehalose-6-soybean fatty acidester as a yellowish viscous syrup, which contained 6-linoleyl-trehaloseas a primary component.

EXAMPLE 5 Preparation of trehalose-6-palm Oil Fatty Acid Ester

[0045] The procedures of Example 4 were repeated with the exception that60 g of a methylester of palm oil fatty acid were used instead of 60 gof methylester of soybean fatty acid to obtain 34.9 g oftrehalose-6-palm oil fatty acid ester as a yellowish viscous syrup,which contained 6-lauroyl-trehalose as a primary component.

[0046] Safety Test

[0047] As a safety test on the above trehalose-6-fatty acid esters,irritation to skin was examinaed in accordance with the followingprocedures.

[0048] An adhesive plaster for patch test which had been impregnatedwith 1 ml of a 0.2% solution of the surfactant was put on 20 subjectsfor 24 hours. Irritaion was evaluated 24 hours after removing the patch.The result was rated by percentage of positive subjects who showed anclear erythema. The results are as shown in Table 1. Sodiumlaurylphosphate used as a control is a surfactant which is usually usedin shampoos, body shampoos and the like. TABLE 1 Irritation to skin,positive, % Sample (0.1% solution) 6-(10-Undecylenyl)-trehalose 06-Lauroyl-trehalose 0 6-Stearoyl-trehalose 0 Trehalose-6-soybean fattyacid ester 0 Trehalose-6-palm fatty acid ester 0 Control (Monosodiumlauryl phosphate) 0.5

[0049] As seen from Table 1, the trehalose-6-fatty acid ester of theinvention has no irritation to skin and has excellent safety to skin.

EXAMPLES 6-8 Preparation of a Skin Washing Agent

[0050] Liquid skin washing agents having the compositions shown in Table2 were prepared using the 6-(10-undecylenyl)-trehalose,6-laurolyl-trehalose, trehalose-6-palm oil fatty acid ester preparedabove. These washing agents were used to wash face. Soil was removedcompletely and the feeling was fine. TABLE 2 Example 6 Example 7 Example8 Component wt. % wt. % wt. % 6-(1-Undecylenyl)- 25.0 — — trehalose6-Lauroyl-trehalose — 15.0 — Trehalose-6-palm oil — — 25.0 fatty acidester Miranol C2M  5.0  5.0  5.0 (Miranol) Glycerine 10.0 10.0 10.0Carboxyvinyl polymer  0.6  0.6  0.6 Perfume (citrus  0.4  0.4  0.4 typecomposition) Water 59.0 69.0 59.0

EXAMPLES 9 AND 10 Preparation of a Hair Washing Agent

1. A surfactant comprising at least one trehalose-6-fatty acid esterrepresented by the following formula:

wherein R represents a saturated or unsaturated acyl group having 8-22carbon atoms, and may have a hydroxy group or other substituents.
 2. Asurfactant comprising at least one trehalose-6-fatty acid estersselected from the group consisting of 6-(10-undecylenyl)-trehalose,6-lauroyl-trehalose, 6-stearoyl-trehalose, trehalose monoisostearate,trehalose monodocosanate, trehalose monolinolenate, trehalosemonocaprate, and trehalose monomyristate.
 3. A washing agent comprisingthe surfactant as claimed in claim
 1. 4. The washing agent as claimed inclaim 3, wherein the washing agent is a hair or skin washing agent. 5.The washing agent as claimed in claim 3, wherein a content of saidtrehalose-6-fatty acid ester is 1-50 wt. %, preferably 10-35 wt. %. 6.An emulsion-type cosmetic composition comprising at least onewater-soluble polymer selected from trehalose-6-fatty acid estersrepresented by the following formula:

wherein R represents a saturated or unsaturated acyl group having 8-22carbon atoms, and may have a hydroxyl group or other substituents.
 7. Anemulsion-type cosmetic composition comprising at least onetrehalose-6-fatty acid ester selected from the group consisting of6-(10-undecylenyl)-trehalose, 6-lauroyl-trehalose, 6-stearoyl-trehalose,trehalose monoisostearate, trehalose monodocosanate, trehalosemonolinolenate, trehalose monocaprate, and trehalose monomyristate, anda water-soluble polymer.
 8. The emulsion-type cosmetic composition asclaimed in claim 6, wherein said water-soluble polymer is one or more ofwater-soluble polymers selected from the group consisting of guar gum,roastbean gum, queensseed, carageenan, galactan, arabic gum, tragacanth,pectin, mannan, starch, xanthan gum, dextrin, succinoglucan, curdlan,gelatin, casein, albumin, collagen, methyl cellulose, ethyl cellulose,hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethylcellulose, methylhydroxypropyl cellulose, soluble starch, carboxymethylstarch, methyl starch, propyleneglycol alginate, salts of alginic acid,polyvinylalcohol, polyvinylpyrrolidone, polyvinylmethylether,carboxyvinyl polymers, sodium polyacrylate, polyethyleneglycol, ethyleneoxide/propylene oxide copolymers, cationated cellulose, sodiumchondroitin sulfate and sodium hyaluronate.
 9. The emulsion-typecosmetic composition as claimed in claim 6, wherein a content of saidtrehalose-6-fatty acid ester is 0.01-20 wt. %, preferably 0.1-10 wt. %and a content of said water-soluble polymer is 0.001-40 wt. %,preferably 0.01-20 wt. %.
 10. The emulsion-type cosmetic composition asclaimed in claim 6, wherein said emulsion-type cosmetic composition is amassage cream, a cleansing cream, a skin cream, a foundation cream, amakeup base, a hair cream, a massage jelly or a medicinal jelly.
 11. Aliposome comprising a membrane wall composed of a trehalose fatty acidester.
 12. The liposome as claimed in claim 11, wherein said trehalosefatty acid ester is trehalose difatty acid ester.
 13. The liposome asclaimed in claim 11, wherein fatty acid of which said trehalose fattyacid ester is constituted is a saturated or unsaturated fatty acid whichhas 8-22 carbon atoms, preferably 10-18 carbon atoms, and may have ahydroxyl group or other substituents.
 14. A liposome comprising amembrane wall mainly composed of at least one trehalose fatty acid esterselected from the group consisting of trehalose dilaurate, trehalosedipalmitate, trehalose diundecylenate, trehalose dimyristate andtrehalose distearate.